Heavy vehicles such as buses, motor homes, and the like are often provided with rear mounted engines which are located behind the rear axles. In such heavy vehicles, the chassis supports mechanical components such as the engine, drive train, suspension and braking systems. Such vehicles typically include the chassis, a superstructure, and a body.
The heavy vehicles require heavy engines for propulsion. In recreational vehicle applications, rear engine placement is preferred in order to avoid the extension into the front of the vehicle of a large engine housing as well as the excessive noise to which occupants of the vehicle would be subjected.
Conventional chassis for such vehicles utilize a common rail height from the front of the vehicle to the rear of the vehicle. The rails, commonly located at opposite lateral sides of the vehicle, serve to mount and support the engine, suspension, transmission and cooling package. The height of the rails above ground level is dictated by the height of the vehicle suspension. In such assemblies, the engine may be positioned between the rails. However, such placement causes difficulty in access to the sides of the engine for servicing of components. The height of the engine mounting also requires a higher than desirable floor height within the coach body often requiring the use of steps inside the coach. Accordingly, a need exists for improved chassis designs and configurations for heavy vehicles.